A word from Melissa, the 'Spam Musubi' costume creator:

My 9 month old son, Satoru, was a spam musubi. Spam musubi is a very popular snack in Hawaii made in the tradition of Japanese onigiri. Spam musubi is composed of a block of rice with a slice of grilled spam on top and nori (seaweed) wrapping to hold it together.

My father-in-law gave me some styrofoam that is typically thrown away at his work. I cut it in the shape of a giant slice of spam. I covered it in a pinkish material and used black material as the nori. He wore all white (the rice) and voila! :)

I attached a picture of a real spam musubi and a picture of my son. :)